Minecarts seem to have changed their behavior in 1.16.1 (not in 1.16) and no longer move as before.

There is a setup I use for moving a zombie in a minecart to convert villagers, and it uses an iteration of a rail and a powered rail alternatively. Whenever I wanted to make the minecart stop I would depower a rail and this would make the minecart stop at that spot even while traveling at full speed.

Now the minecart won't make a stop unless it is traveling significantly slower. 

I haven't seen update logs related to this change, therefore I'm considering it a bug.